Deep inelastic e-τ and μ-τ Conversion in the NA64 experiment at the CERN SPS

Sergei Gninenko, Sergey Kovalenko, Serguei Kuleshov, Valery E. Lyubovitskij, Alexey S. Zhevlakov

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


© 2018 authors. Published by the American Physical Society. We study the lepton flavor violating (LFV) e(μ)-τ conversion in deep inelastic scattering (DIS) of electrons (muons) on fixed-target nuclei. Our model-independent analysis is based on the set of low-energy effective four-fermion LFV operators composed of leptons and quarks with the corresponding mass scales Λk for each operator. Using the estimated sensitivity of the search for this LFV process in events with large missing energy in the NA64 experiment at the CERN SPS, we derive lower limits for Λk and compared them with the corresponding limits existing in the literature. We show that the DIS e(μ)-τ conversion is able to provide a plenty of new limits as yet nonexisting in the literature. We also analyzed the energy spectrum of the final-state τ and discussed the viability of the observation of this process in the NA64 experiment and ones akin to it. The case of polarized beams and targets is also discussed.
Original languageEnglish
JournalPhysical Review D
Publication statusPublished - 1 Jul 2018
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


Dive into the research topics of 'Deep inelastic e-τ and μ-τ Conversion in the NA64 experiment at the CERN SPS'. Together they form a unique fingerprint.

Cite this